Acaena microphylla, the bidibid or piripiri,[4] and outside New Zealand, New Zealand-bur,[5] is a small herbaceous, prostrate perennialflowering plant in the rose family Rosaceae, native to both the North and South Islands of New Zealand.[2] There are two varieties:
Hooker describes it as "a very small and glabrous species; the leaflets not 1/4 in. long. Capitula very large for the size of the plant, upwards of an inch across, including the spines, which are not barbate, and distinguish it as a species."[3]
Taxonomy and naming
Acaena microphylla was first formally described in 1852 by Joseph Dalton Hooker.[2][3] The genus name Acaena is derived from the ancient Greek word akaina, meaning "thorn" or "spine",[7] referring to the spiny calyx of many species of Acaena. The specific epithetmicrophylla derives from the Greek words, mikros (small) and phyllon (leaf), to give an adjective meaning "small-leaved".[8]
In 2013, the variety Acaena microphylla var. pauciglochidiata was classified as "At Risk - Naturally Uncommon" under the New Zealand Threat Classification System. By 2018, due to an actual decline, the status changed to "At Risk - Declining". (The area of occupancy had decreased to 100 km2 or less, and the predicted decline was 10 to 50%).[1] However, the variety Acaena microphylla var. microphylla was classified as "Not Threatened" in 2004, 2009 and 2012,[4] and again in 2018.[1]
